1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MODULE_PARAMS_H
3 #define _LINUX_MODULE_PARAMS_H
4 /* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
5 #include <linux/init.h>
6 #include <linux/stringify.h>
7 #include <linux/kernel.h>
9 /* You can override this manually, but generally this should match the
12 #define MODULE_PARAM_PREFIX /* empty */
13 #define __MODULE_INFO_PREFIX /* empty */
15 #define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
16 /* We cannot use MODULE_PARAM_PREFIX because some modules override it. */
17 #define __MODULE_INFO_PREFIX KBUILD_MODNAME "."
20 /* Chosen so that structs with an unsigned long line up. */
21 #define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
23 #define __MODULE_INFO(tag, name, info) \
24 static const char __UNIQUE_ID(name)[] \
25 __used __attribute__((section(".modinfo"), unused, aligned(1))) \
26 = __MODULE_INFO_PREFIX __stringify(tag) "=" info
28 #define __MODULE_PARM_TYPE(name, _type) \
29 __MODULE_INFO(parmtype, name##type, #name ":" _type)
31 /* One for each parameter, describing how to use it. Some files do
32 multiple of these per line, so can't just use MODULE_INFO. */
33 #define MODULE_PARM_DESC(_parm, desc) \
34 __MODULE_INFO(parm, _parm, #_parm ":" desc)
39 * Flags available for kernel_param_ops
41 * NOARG - the parameter allows for no argument (foo instead of foo=1)
44 KERNEL_PARAM_OPS_FL_NOARG = (1 << 0)
47 struct kernel_param_ops {
48 /* How the ops should behave */
50 /* Returns 0, or -errno. arg is in kp->arg. */
51 int (*set)(const char *val, const struct kernel_param *kp);
52 /* Returns length written or -errno. Buffer is 4k (ie. be short!) */
53 int (*get)(char *buffer, const struct kernel_param *kp);
54 /* Optional function to free kp->arg when module unloaded. */
55 void (*free)(void *arg);
59 * Flags available for kernel_param
61 * UNSAFE - the parameter is dangerous and setting it will taint the kernel
62 * HWPARAM - Hardware param not permitted in lockdown mode
65 KERNEL_PARAM_FL_UNSAFE = (1 << 0),
66 KERNEL_PARAM_FL_HWPARAM = (1 << 1),
72 const struct kernel_param_ops *ops;
78 const struct kparam_string *str;
79 const struct kparam_array *arr;
83 extern const struct kernel_param __start___param[], __stop___param[];
85 /* Special one for strings we want to copy into */
86 struct kparam_string {
91 /* Special one for arrays */
95 unsigned int elemsize;
97 const struct kernel_param_ops *ops;
102 * module_param - typesafe helper for a module/cmdline parameter
103 * @value: the variable to alter, and exposed parameter name.
104 * @type: the type of the parameter
105 * @perm: visibility in sysfs.
107 * @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
108 * ".") the kernel commandline parameter. Note that - is changed to _, so
109 * the user can use "foo-bar=1" even for variable "foo_bar".
111 * @perm is 0 if the the variable is not to appear in sysfs, or 0444
112 * for world-readable, 0644 for root-writable, etc. Note that if it
113 * is writable, you may need to use kernel_param_lock() around
114 * accesses (esp. charp, which can be kfreed when it changes).
116 * The @type is simply pasted to refer to a param_ops_##type and a
117 * param_check_##type: for convenience many standard types are provided but
118 * you can create your own by defining those variables.
120 * Standard types are:
121 * byte, short, ushort, int, uint, long, ulong
122 * charp: a character pointer
123 * bool: a bool, values 0/1, y/n, Y/N.
124 * invbool: the above, only sense-reversed (N = true).
126 #define module_param(name, type, perm) \
127 module_param_named(name, name, type, perm)
130 * module_param_unsafe - same as module_param but taints kernel
132 #define module_param_unsafe(name, type, perm) \
133 module_param_named_unsafe(name, name, type, perm)
136 * module_param_named - typesafe helper for a renamed module/cmdline parameter
137 * @name: a valid C identifier which is the parameter name.
138 * @value: the actual lvalue to alter.
139 * @type: the type of the parameter
140 * @perm: visibility in sysfs.
142 * Usually it's a good idea to have variable names and user-exposed names the
143 * same, but that's harder if the variable must be non-static or is inside a
144 * structure. This allows exposure under a different name.
146 #define module_param_named(name, value, type, perm) \
147 param_check_##type(name, &(value)); \
148 module_param_cb(name, ¶m_ops_##type, &value, perm); \
149 __MODULE_PARM_TYPE(name, #type)
152 * module_param_named_unsafe - same as module_param_named but taints kernel
154 #define module_param_named_unsafe(name, value, type, perm) \
155 param_check_##type(name, &(value)); \
156 module_param_cb_unsafe(name, ¶m_ops_##type, &value, perm); \
157 __MODULE_PARM_TYPE(name, #type)
160 * module_param_cb - general callback for a module/cmdline parameter
161 * @name: a valid C identifier which is the parameter name.
162 * @ops: the set & get operations for this parameter.
163 * @perm: visibility in sysfs.
165 * The ops can have NULL set or get functions.
167 #define module_param_cb(name, ops, arg, perm) \
168 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, 0)
170 #define module_param_cb_unsafe(name, ops, arg, perm) \
171 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1, \
172 KERNEL_PARAM_FL_UNSAFE)
175 * <level>_param_cb - general callback for a module/cmdline parameter
176 * to be evaluated before certain initcall level
177 * @name: a valid C identifier which is the parameter name.
178 * @ops: the set & get operations for this parameter.
179 * @perm: visibility in sysfs.
181 * The ops can have NULL set or get functions.
183 #define __level_param_cb(name, ops, arg, perm, level) \
184 __module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level, 0)
186 #define core_param_cb(name, ops, arg, perm) \
187 __level_param_cb(name, ops, arg, perm, 1)
189 #define postcore_param_cb(name, ops, arg, perm) \
190 __level_param_cb(name, ops, arg, perm, 2)
192 #define arch_param_cb(name, ops, arg, perm) \
193 __level_param_cb(name, ops, arg, perm, 3)
195 #define subsys_param_cb(name, ops, arg, perm) \
196 __level_param_cb(name, ops, arg, perm, 4)
198 #define fs_param_cb(name, ops, arg, perm) \
199 __level_param_cb(name, ops, arg, perm, 5)
201 #define device_param_cb(name, ops, arg, perm) \
202 __level_param_cb(name, ops, arg, perm, 6)
204 #define late_param_cb(name, ops, arg, perm) \
205 __level_param_cb(name, ops, arg, perm, 7)
207 /* On alpha, ia64 and ppc64 relocations to global data cannot go into
208 read-only sections (which is part of respective UNIX ABI on these
209 platforms). So 'const' makes no sense and even causes compile failures
210 with some compilers. */
211 #if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
212 #define __moduleparam_const
214 #define __moduleparam_const const
217 /* This is the fundamental function for registering boot/module
219 #define __module_param_call(prefix, name, ops, arg, perm, level, flags) \
220 /* Default value instead of permissions? */ \
221 static const char __param_str_##name[] = prefix #name; \
222 static struct kernel_param __moduleparam_const __param_##name \
224 __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
225 = { __param_str_##name, THIS_MODULE, ops, \
226 VERIFY_OCTAL_PERMISSIONS(perm), level, flags, { arg } }
228 /* Obsolete - use module_param_cb() */
229 #define module_param_call(name, _set, _get, arg, perm) \
230 static const struct kernel_param_ops __param_ops_##name = \
231 { .flags = 0, .set = _set, .get = _get }; \
232 __module_param_call(MODULE_PARAM_PREFIX, \
233 name, &__param_ops_##name, arg, perm, -1, 0)
236 extern void kernel_param_lock(struct module *mod);
237 extern void kernel_param_unlock(struct module *mod);
239 static inline void kernel_param_lock(struct module *mod)
242 static inline void kernel_param_unlock(struct module *mod)
249 * core_param - define a historical core kernel parameter.
250 * @name: the name of the cmdline and sysfs parameter (often the same as var)
252 * @type: the type of the parameter
253 * @perm: visibility in sysfs
255 * core_param is just like module_param(), but cannot be modular and
256 * doesn't add a prefix (such as "printk."). This is for compatibility
257 * with __setup(), and it makes sense as truly core parameters aren't
258 * tied to the particular file they're in.
260 #define core_param(name, var, type, perm) \
261 param_check_##type(name, &(var)); \
262 __module_param_call("", name, ¶m_ops_##type, &var, perm, -1, 0)
265 * core_param_unsafe - same as core_param but taints kernel
267 #define core_param_unsafe(name, var, type, perm) \
268 param_check_##type(name, &(var)); \
269 __module_param_call("", name, ¶m_ops_##type, &var, perm, \
270 -1, KERNEL_PARAM_FL_UNSAFE)
275 * module_param_string - a char array parameter
276 * @name: the name of the parameter
277 * @string: the string variable
278 * @len: the maximum length of the string, incl. terminator
279 * @perm: visibility in sysfs.
281 * This actually copies the string when it's set (unlike type charp).
282 * @len is usually just sizeof(string).
284 #define module_param_string(name, string, len, perm) \
285 static const struct kparam_string __param_string_##name \
287 __module_param_call(MODULE_PARAM_PREFIX, name, \
289 .str = &__param_string_##name, perm, -1, 0);\
290 __MODULE_PARM_TYPE(name, "string")
293 * parameq - checks if two parameter names match
294 * @name1: parameter name 1
295 * @name2: parameter name 2
297 * Returns true if the two parameter names are equal.
298 * Dashes (-) are considered equal to underscores (_).
300 extern bool parameq(const char *name1, const char *name2);
303 * parameqn - checks if two parameter names match
304 * @name1: parameter name 1
305 * @name2: parameter name 2
306 * @n: the length to compare
308 * Similar to parameq(), except it compares @n characters.
310 extern bool parameqn(const char *name1, const char *name2, size_t n);
312 /* Called on module insert or kernel boot */
313 extern char *parse_args(const char *name,
315 const struct kernel_param *params,
320 int (*unknown)(char *param, char *val,
321 const char *doing, void *arg));
323 /* Called by module remove. */
325 extern void destroy_params(const struct kernel_param *params, unsigned num);
327 static inline void destroy_params(const struct kernel_param *params,
331 #endif /* !CONFIG_SYSFS */
333 /* All the helper functions */
334 /* The macros to do compile-time type checking stolen from Jakub
335 Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
336 #define __param_check(name, p, type) \
337 static inline type __always_unused *__check_##name(void) { return(p); }
339 extern const struct kernel_param_ops param_ops_byte;
340 extern int param_set_byte(const char *val, const struct kernel_param *kp);
341 extern int param_get_byte(char *buffer, const struct kernel_param *kp);
342 #define param_check_byte(name, p) __param_check(name, p, unsigned char)
344 extern const struct kernel_param_ops param_ops_short;
345 extern int param_set_short(const char *val, const struct kernel_param *kp);
346 extern int param_get_short(char *buffer, const struct kernel_param *kp);
347 #define param_check_short(name, p) __param_check(name, p, short)
349 extern const struct kernel_param_ops param_ops_ushort;
350 extern int param_set_ushort(const char *val, const struct kernel_param *kp);
351 extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
352 #define param_check_ushort(name, p) __param_check(name, p, unsigned short)
354 extern const struct kernel_param_ops param_ops_int;
355 extern int param_set_int(const char *val, const struct kernel_param *kp);
356 extern int param_get_int(char *buffer, const struct kernel_param *kp);
357 #define param_check_int(name, p) __param_check(name, p, int)
359 extern const struct kernel_param_ops param_ops_uint;
360 extern int param_set_uint(const char *val, const struct kernel_param *kp);
361 extern int param_get_uint(char *buffer, const struct kernel_param *kp);
362 #define param_check_uint(name, p) __param_check(name, p, unsigned int)
364 extern const struct kernel_param_ops param_ops_long;
365 extern int param_set_long(const char *val, const struct kernel_param *kp);
366 extern int param_get_long(char *buffer, const struct kernel_param *kp);
367 #define param_check_long(name, p) __param_check(name, p, long)
369 extern const struct kernel_param_ops param_ops_ulong;
370 extern int param_set_ulong(const char *val, const struct kernel_param *kp);
371 extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
372 #define param_check_ulong(name, p) __param_check(name, p, unsigned long)
374 extern const struct kernel_param_ops param_ops_ullong;
375 extern int param_set_ullong(const char *val, const struct kernel_param *kp);
376 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
377 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
379 extern const struct kernel_param_ops param_ops_charp;
380 extern int param_set_charp(const char *val, const struct kernel_param *kp);
381 extern int param_get_charp(char *buffer, const struct kernel_param *kp);
382 extern void param_free_charp(void *arg);
383 #define param_check_charp(name, p) __param_check(name, p, char *)
385 /* We used to allow int as well as bool. We're taking that away! */
386 extern const struct kernel_param_ops param_ops_bool;
387 extern int param_set_bool(const char *val, const struct kernel_param *kp);
388 extern int param_get_bool(char *buffer, const struct kernel_param *kp);
389 #define param_check_bool(name, p) __param_check(name, p, bool)
391 extern const struct kernel_param_ops param_ops_bool_enable_only;
392 extern int param_set_bool_enable_only(const char *val,
393 const struct kernel_param *kp);
394 /* getter is the same as for the regular bool */
395 #define param_check_bool_enable_only param_check_bool
397 extern const struct kernel_param_ops param_ops_invbool;
398 extern int param_set_invbool(const char *val, const struct kernel_param *kp);
399 extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
400 #define param_check_invbool(name, p) __param_check(name, p, bool)
402 /* An int, which can only be set like a bool (though it shows as an int). */
403 extern const struct kernel_param_ops param_ops_bint;
404 extern int param_set_bint(const char *val, const struct kernel_param *kp);
405 #define param_get_bint param_get_int
406 #define param_check_bint param_check_int
409 * module_param_array - a parameter which is an array of some type
410 * @name: the name of the array variable
411 * @type: the type, as per module_param()
412 * @nump: optional pointer filled in with the number written
413 * @perm: visibility in sysfs
415 * Input and output are as comma-separated values. Commas inside values
416 * don't work properly (eg. an array of charp).
418 * ARRAY_SIZE(@name) is used to determine the number of elements in the
419 * array, so the definition must be visible.
421 #define module_param_array(name, type, nump, perm) \
422 module_param_array_named(name, name, type, nump, perm)
425 * module_param_array_named - renamed parameter which is an array of some type
426 * @name: a valid C identifier which is the parameter name
427 * @array: the name of the array variable
428 * @type: the type, as per module_param()
429 * @nump: optional pointer filled in with the number written
430 * @perm: visibility in sysfs
432 * This exposes a different name than the actual variable name. See
433 * module_param_named() for why this might be necessary.
435 #define module_param_array_named(name, array, type, nump, perm) \
436 param_check_##type(name, &(array)[0]); \
437 static const struct kparam_array __param_arr_##name \
438 = { .max = ARRAY_SIZE(array), .num = nump, \
439 .ops = ¶m_ops_##type, \
440 .elemsize = sizeof(array[0]), .elem = array }; \
441 __module_param_call(MODULE_PARAM_PREFIX, name, \
443 .arr = &__param_arr_##name, \
445 __MODULE_PARM_TYPE(name, "array of " #type)
448 hwparam_ioport, /* Module parameter configures an I/O port */
449 hwparam_iomem, /* Module parameter configures an I/O mem address */
450 hwparam_ioport_or_iomem, /* Module parameter could be either, depending on other option */
451 hwparam_irq, /* Module parameter configures an IRQ */
452 hwparam_dma, /* Module parameter configures a DMA channel */
453 hwparam_dma_addr, /* Module parameter configures a DMA buffer address */
454 hwparam_other, /* Module parameter configures some other value */
458 * module_param_hw_named - A parameter representing a hw parameters
459 * @name: a valid C identifier which is the parameter name.
460 * @value: the actual lvalue to alter.
461 * @type: the type of the parameter
462 * @hwtype: what the value represents (enum hwparam_type)
463 * @perm: visibility in sysfs.
465 * Usually it's a good idea to have variable names and user-exposed names the
466 * same, but that's harder if the variable must be non-static or is inside a
467 * structure. This allows exposure under a different name.
469 #define module_param_hw_named(name, value, type, hwtype, perm) \
470 param_check_##type(name, &(value)); \
471 __module_param_call(MODULE_PARAM_PREFIX, name, \
472 ¶m_ops_##type, &value, \
474 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
475 __MODULE_PARM_TYPE(name, #type)
477 #define module_param_hw(name, type, hwtype, perm) \
478 module_param_hw_named(name, name, type, hwtype, perm)
481 * module_param_hw_array - A parameter representing an array of hw parameters
482 * @name: the name of the array variable
483 * @type: the type, as per module_param()
484 * @hwtype: what the value represents (enum hwparam_type)
485 * @nump: optional pointer filled in with the number written
486 * @perm: visibility in sysfs
488 * Input and output are as comma-separated values. Commas inside values
489 * don't work properly (eg. an array of charp).
491 * ARRAY_SIZE(@name) is used to determine the number of elements in the
492 * array, so the definition must be visible.
494 #define module_param_hw_array(name, type, hwtype, nump, perm) \
495 param_check_##type(name, &(name)[0]); \
496 static const struct kparam_array __param_arr_##name \
497 = { .max = ARRAY_SIZE(name), .num = nump, \
498 .ops = ¶m_ops_##type, \
499 .elemsize = sizeof(name[0]), .elem = name }; \
500 __module_param_call(MODULE_PARAM_PREFIX, name, \
502 .arr = &__param_arr_##name, \
504 KERNEL_PARAM_FL_HWPARAM | (hwparam_##hwtype & 0)); \
505 __MODULE_PARM_TYPE(name, "array of " #type)
508 extern const struct kernel_param_ops param_array_ops;
510 extern const struct kernel_param_ops param_ops_string;
511 extern int param_set_copystring(const char *val, const struct kernel_param *);
512 extern int param_get_string(char *buffer, const struct kernel_param *kp);
514 /* for exporting parameters in /sys/module/.../parameters */
518 #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
519 extern int module_param_sysfs_setup(struct module *mod,
520 const struct kernel_param *kparam,
521 unsigned int num_params);
523 extern void module_param_sysfs_remove(struct module *mod);
525 static inline int module_param_sysfs_setup(struct module *mod,
526 const struct kernel_param *kparam,
527 unsigned int num_params)
532 static inline void module_param_sysfs_remove(struct module *mod)
536 #endif /* _LINUX_MODULE_PARAMS_H */